1. Field of the Invention
The present invention relates to a television signal receiving system, and more particularly, to a television signal receiving system for use with a cable television broadcast otherwise known as a CATV broacast.
2. Description of the Prior Art
In the U.S.A., for example, conventional VHF television broadcasts are carried out by assigning channels 2 to 13 with the available frequency band, as shown in FIG. 1A. In case of the CATV broadcast, however, as shown in FIG. 1B, channels A to W (A to I and J to W) in the vacant frequency band portion of the conventional VHF television broadcast frequency band are also used. In the case of a CATV broadcast, the signals of the additional CATV channels (channels A to W) and the signals of the conventional VHF channels 2 to 13 are transmitted together along a coaxial cable.
There is a system in which special broadcasts are transmitted along certain channels among the additional CATV channels. An ordinary viewer can not receive the special broadcasts without paying a fee. The special channel is called a pay-channel, and a viewer rents a receiving adaptor in order to receive the special broadcasts on the pay-channels. The receiving adaptor is called a descrambler.
The additional CATV channels are usually divided into free CATV channels and pay-channels. In order to receive the conventional VHF channels, the free CATV channels the pay-channels with a prior art descrambler, it is necessary for a viewer not only to switch the channel of a television receiver but also to switch the channel of the descrambler. This is rather complicated just for watching television.
Further, even though prior art television receivers have remote control operation for changing channels, the descrambler (generally provided separately) can not be controlled by such a remote control. Thus, channel changing can not be performed by the remote control. Even if it is possible, a special remote control system must be employed. In other words, the prior art remote control system can not be used as it is, and is incomplete.